Consider the following function on R (x) = 2x + 2x, c> 0. (a) Is f coercive? Justify your answer. (b) Find all the local and global minimizers of f. Justify your answer. (c) We apply the gradient method with the exact line search starting from the initial value (c, 1). Find the optimal step-size * 20. (d) Using from above, find the closed-form expression for the function values f(x) for all t > 1. (e) Classify the convergence of the gradient method on this problem as sublinear, linear, superlinear, or quadratic. Explain your reasoning.